S13 CA18DET Fault codes with no apparent faults?!?

[Wasson Will]

Just had the car off the road again to do some body workwork and clutch/gearbox, got it running again a month ago all working perfectly, MOT last week all fine and fueling as normal, driving a few days ago noticed it was running very rich when warm. Plugged in the laptop and noticed engine temp was only reading 50 deg when hot, checked the senor and turns out the retainer clip has been broken since I owned the car and the plug was not sitting correctly so removed and contact cleaner both sides put back together and straight up to 85 again and all seemed well when I drove home.

Then used later and running super rich again, heavy when driving and creeps straight up to 10 to 1 on the Wideband as soon as ticking over, plugged in the laptop expecting to see the same problem again but when hooked up temp readings as expected however I now have three Fault code reading that I cannot clear.

Warning Coolant temp fault, check sensor resistance/ wiring continuity
Warning TPS fault, check sensor resistance/ wiring continuity
Warning Knock Sensor fault resistance, check sensor/ wiring continuity


Whilst driving the the TPS and temp seem to be giving consistent readings, have been out today to fault find and but there does not appear to be a problem when viewed from the software. The attached log is taken with ignition on but engine not running whilst cold temp reading seems accurate for ambient temp, knock is reading zero volts and applying throttle from zero to full seems to be giving accurate readings so I am at a loss as to the fault, can this be an ECU or chip issue. I have had the car for nearly ten years and this is one thing that has never given any issues.

I assume it is running so rich as the temp sensor fault is making the ECU disregard the displayed temperature and not using the lamba readings.

Any Ideas? I have separated all the plugs of the involved sensors and cleaned contacts as well as pulling of the main ECU harness plug and contact cleaning that and jiggled/manipulated the wiring loom where I can to see if the sensors react but nothing. I have not checked the individual wire continuities with a meter but that seems pointless as the sensors all appear to be reading correctly.

Cheers Will

[Wasson Will]

Have done a log from cold to running temp and again there seems to be no disparities with the sensor readings but still the fault codes are present and it is running 10/12 to 1 fuel ratio as soon as any throttle is applied even with no boost and it is not using the lamba readings for cruise or tickover.

Have checked the manual for the relevant connections on the ECU,will check continuity later but this seems futile as all appears to be reading correctly at the ECU. What have I overlooked?

[Matt]

ECU flagged some DTC faults for some reason, or its DTC store got corrupted. Clear out the DTCs from the Consult View window and see if they reappear or if it says ECU OK

[Wasson Will]

Yeah have already tried clearing the fault codes from the ECU status window. Tried that repeatedly whilst recording the first short log with the engine not running hence my confusion. If they were randomly re-occuring whilst running I would assume dodgy connection or damaged wire etc but is constant whilst all sensors are giving constant readings.

[Wasson Will]

Just to try and prove the fault with ecu or wiring just plugged in a spare ECU and used the old style checker box to read faults. With a different ECU put into diagnostic modes three for fault codes and just got the standard 55 code which I believe is no faults. Was unable to start as injectors and MAF are wrong. Had a look inside the ecu to make sure there where no obvious signs of damp ingress or blown components. All clean. Plugged it back in and same faults again unable to clear with ignition on.

[Matt]

Wrong window... I said Consult View window

Until the recent versions ECU Status only clear messages, not the fault codes

[Wasson Will]

Yeah sorry about that, sign of the Nissan that I have never needed to clear a fault code in the 10 years I have had the car. Seems like there was an intermittent issue with the knock sensor. Getting no codes again now but, has been progressively worse over time and now is running horrifically rich on the same map that it was running pre gearbox change to the point it cooked the head and killed the narrow band lamda sensor I believe(my fault for driving it even though i knew it wasn't right) Head checked and gasket down, lamda working again. Still running like a pig on the original tuned map, to the point as soon as you go anywheere near boost afr goes sub 10 or there abouts and it drowns out. Have just been leaning off the map which is improving it massively but I am leaning it off a massive amount which is clearly making me wonder why... That said the head change I have just done has swapped out the split port eco head that was fitted for a normal all port open head, this will have changed the flow behavior a little but no this significantly I doubt.

The issue I have now is that I cannot get any of my PLX stuff to interface with nistune, had split the chain to run AFR seperately from the EGT and boost previously. However since getting the car back on the road in September, cannot get any of them to sync with the software.

I know you have said that the wideband window will not handle the PLX shit but is not working in the log part either. Have tried configuring for afr to aux 4 in and pulling in the look up tables afr1 and afr2 but gets a momentary reading and then crashes/ repeatedly times out connection. Same if I try and connect the egt and boost as well. Am currently going to search for another USB lead just to make sure that is not the problem... Obviousl;y ity is a nightmare as I can't really try and sort out the rich running without the logging of afrs and boost.

[Wasson Will]

Just been playing in my mind that it appears to have been even worse since the head was changed.... Had to change the fuel rail as well to fitted the different manifold inlets, checked fuel pressure and at 45 psi. Sure when I setup the car after rebuild with the old fuel rail it was 38/40 psi so this would explain the richness of the map. Since before I owned the car the vacuum has been disconnected on the fuel pressure regulator presumably to suit the stage 2 chip that was fitted. Would you recommend reinstating the regulator vacuum.

[Matt]

On earlier Nissan ECUs, Fault codes are generally triggered and then you clear them following the diagnostic procedure in the service manual

Good that you are not getting any codes now

I've read about in this post about it getting richer:
viewtopic.php?f=7&t=3615&p=27742

So can continue that discussion there. I'm not sure how the head got cooked (cooling system is separate to spark and fuel)

I've posted in the other thread about what I need for the PLX stuff (debug log)

About 5psi will make a little difference and the vacuum line is needed to be connected to raise fuel pressure 1psi per each point of boost

[Matt]

you have said that the wideband window will not handle the PLX shit but is not working in the log part either. Have tried configuring for afr to aux 4 in and pulling in the look up tables afr1 and afr2 but gets a momentary reading and then crashes/ repeatedly times out connection.

I've fixed up the wideband window, so it now shows the PLX stuff. But you can right click and add gauges on the background to show all the PLX stuff

When you say it 'crashes', so is the software shutting down? Did you send a crash report. Make sure to run the latest version 1.3.25 or later and I'll check out the crash reports. I tend not to look at crash reports more than several versions older since those will show any old crashes that I've already fixed

With the timeout, I'll need to look into that. Please make a debug log using File > Config> Misc > Debug logging. Attempt connection several times and then post the debug log here. I'll see what is going on with the connection. I've got other customers using PLX who have emailed me logs from their wideband, so not sure why yours is not working. It might be the selections? Maybe just start with AFR1 only and then see if you get it connected with that, before adding extra inputs to the chain.